Issue 80: A Closer Look at H1N1

H1N1. We’ve been watching it since last spring and now it’s made its presence known, sometimes with a vengeance. And while we don’t know everything about this pandemic-causing virus and its effects, we do know more than we did.

Until recently, the CDC said 1,000 people have died from H1N1. The New York Times, however, reported that number as too low and that, in fact, about 4,000 people have already perished due to H1N1-related complications—including pneumonia and bacterial infections. Federal health officials now confirm this number: 4,000 or more have died from H1N1.

That matches up with what others know about H1N1.

An analysis of more than 1,000 hospitalized California patients with H1N1 gleaned these results: infants are most likely to be admitted to the hospital, while patients 50+ are most likely to die once admitted with H1N1. Of the 1,088 California patients studied in this analysis, 118 died and 340 of them were admitted to intensive-care units. In those 50+, the death rate was about 10 times the amount of that in patients under age 18.

Older people, however, are less likely than children and young adults to contract H1N1 in the first place. The study suggests, too, that the overweight may be more at risk. The study focused on those hospitalized between April 23rd and August 11th and was published in the Journal of the American Medical Association.

Other findings indicate this flu often attacks the lungs, has its origins with the Spanish flu that swept across the globe in 1918 (killing an estimated 675,000 Americans), and that it’s not adequately verified by rapid influenza diagnostic tests.

This H1N1 strain is known to attack the lungs, causing blood clots and bleeding. Some patients’ lungs are so bad that doctors bypass them with an ECMO—extra-corporeal membrane oxygenation—which works like a heart-lung machine used during heart surgery. For the extremely overweight, lung damage may be exacerbated, due to unhealthy inflammation levels that often accompany increased weight levels, according to Ali El Solh, an associate professor of medicine and social and preventive medicine at the State University of New York-Buffalo.

One hospital worker says the lung damage from H1N1 is reminiscent of the 1918 flu, which also ravaged the lungs. And speaking of the Spanish flu of 1918…a Kansas State researcher, Juergen Richt, Regents Distinguished Professor of Diagnostic Medicine and Pathobiology at K-State’s College of Veterinary Medicine, says his team’s research indicates that the 1918 pandemic influenza virus and a virus causing the swine flu at that time were the same virus—and the forefather to this current H1N1 virus.

Simply put, the 1918 virus spread through the pig population, adapted to the swine and came out as the current H1N1 swine influenza virus—which is a new combination of swine, avian and human genes. Their results are published in the Journal of Virology.

To add to the mix, the rapid influenza diagnostic test may not be as accurate as previously thought in determining who has H1N1. A growing body of evidence suggests that it might be doing a rather poor job of verifying H1N1 cases—even though it is still used in doctors’ offices and emergency departments.

Scientists report (in The Journal of the American Medical Association) that one-third of California patients hospitalized with H1N1 displayed a negative rapid test—the one that tests for influenza A virus from swabbing the nose. The problem is that the test is not very sensitive; it can often overlook influenza A, particularly among adults, who don’t typically shed as much of the virus as kids do.

Stephen Baum, an infectious-disease physician at New York’s Albert Einstein College of Medicine says, “I think people are growing a little less confident when they get the results of those tests. If you test positive, you got it. If it’s negative, you may still 'got it'."

And folks sure are getting it.

Recently, in the pediatric emergency room at Johns Hopkins Hospital, nearly three times as many kids as usual came in with the flu. It’s a scene being played out in areas like Denver, Duluth, Seattle and San Diego as well and is also impacting intensive care units.

In short, doctors at Johns Hopkins and elsewhere believe the number of patients needing hospitalization and intensive care will increase. While smaller numbers of flu patients require intensive care, some are so ill they need round-the-clock care for weeks.

All in all, it’s hard to tell what the current H1N1 strain will do from here on out, so stay tuned for more information.

This information is intended for educational and informational
purposes only. It should not be used in place of an individual consultation or examination
or replace the advice of your health care professional and should not be relied upon to determine
diagnosis or course of treatment.